The rotating groups of axial piston pumps and motors are easily damaged by contaminants passing therethrough. The pumps and motors of a closed loop system are much more prone to damage by contaminants within the system since the majority of the fluid within a closed loop system is simply recirculated through the pumps and motors with only a small portion of the fluid being taken from the system and passed through a filter. Thus, one contaminant may pass through the pump and motor many times before it is finally filtered out. The contaminant may inflict some damage to the pump and motor each time it passes therethrough. Thus, it is imperative that the fluid within the closed loop system be kept free of contaminants at all times.
One way of minimizing the risk of contaminants passing through the pump and motor in a closed loop system is to flush the lines or hoses communicating the pump with the motor prior to operating the system after repairs are made to the system. It is extremely important that the hoses be flushed if the repairs include replacing one or more of the hoses.
One of the problems heretofore encountered has been the lack of any simple and economical method of flushing a high pressure, closed loop system particularly when the repairs are made at the job site. The heretofore known method includes disconnecting the hoses from the pump and connecting the ends together and then disconnecting the hoses from the motor and connecting the ends to a self-contained flushing apparatus having its own pump, tank and filter. While that flushing procedure was usually done when the repairs were made by a service technician who had the proper equipment, it was seldom done when the repairs were made by an owner not having the proper equipment.
In view of the above, it would be desirable to have a simple and inexpensive apparatus and a method of using the apparatus for easily flushing a high pressure, closed loop hydraulic system in the field after repairs are made thereto. The method utilizes a charge pump normally associated with a closed loop hydraulic system thereby eliminating the need for the self-contained flushing apparatus. The components used for the present flushing method are inexpensive and can be easily installed with tools an owner-operator would normally have.